Propelling means for floor finishing machines

ABSTRACT

The present invention relates to self-propelled floor surfacing units, as for example, a drum type floor sanding machine; and more particularly, to a self-propelled driving unit for such machinery. In the preferred arrangements of the invention, a pair of non-steerable motor driven wheels are provided at the rear of the chassis of the self-propelled unit, and at least one swivetable wheel is provided at the front end of the driving unit. The driving unit is connected to the floor surfacing machine through a draw frame that is hinged at one end to the driving unit and at the other end to the floor surfacing machine in a manner which allows vertical movement between the two units but which restrains all other than vertical movement between the units. A lever fixed to the propelling unit extends along one side of the sanding machine to permit the operator at the rear of the sander to tilt the driving unit and bring its driving wheels out of floor engagement while shifting the weight of the driving unit onto the swivetable wheels, so that the entire unit can be maneuvered sideways over the floor.

United States Patent [191' Sonnenberg [4 1 Feb. 25, 1975 PROPELLING MEANS FOR FLOOR FINISHING MACHINES [76] Inventor: Darwin D. Sonnenberg, Route 1,

Hamler, Ohio 43524 [22] Filed: Feb. 25, 1974 [21] Appl. No.: 445,552

Primary ExaminerJames L. Jones, Jr.

[57] ABSTRACT The present invention relates to self-propelled floor surfacing units, as for example, a drum type floor sanding machine; and more particularly, to a selfpropelled driving unit for such machinery. In the preferred arrangements of the invention, a pair of nonsteerable motor driven wheels are provided at the rear of the chassis of the self-propelled unit, and at least one swivetable wheel is provided at the front end of the driving unit. The driving unit is connected to the floor surfacing machine through a draw frame that is hinged at one end to the driving unit and at the other end to the floor surfacing machine in a manner which allows vertical movement between the two units but which restrains all other than vertical movement between the units. A lever fixed to the propelling unit extends along one side of the sanding machine to permit the operator at the rear of the sander to tilt the driving unit and bring its driving wheels out of floor engagement while shifting the weight of the driving unit onto the swivetable wheels, so that the entire unit can be maneuvered sideways over the floor.

7 Claims, 5 Drawing Figures PATENTED FEB2 5197s SHEET 2 BF 2 PROPELLING MEANS FOR FLOOR FINISHING MACHINES BACKGROUND OF THE INVENTION floor surfacing element, the floor surfacing element is usually carried by bearing structures that are fixed to the chassis of the floor surfacing machine; and the amount of weight that is supplied the floor surfacing element is controlled by adjusting spring suspensions that are positioned between the chassis and the nonsteerable wheels. The remainder of the weight of the floor surfacing machine is carried by a swivetable wheel located at the rear of the machine. The nonsteerable wheels can also be forced downwardly from the chassis sufficiently to raise the floor surfacing element out of engagment with the floor, so that the unit can be shifted laterally and/or steered over the floor.

A problem has existed heretofore in making such structures self-propelled because the non-steerable wheels have little weight thereon when the floor surfacing element is in use, and therefore little traction can be had at the time that the floor surfacing element is performing its work. To my knowledge, therefore, there has not been heretofore a practical self-propelled floor surfacing machine, and particularly a drum sanding machine, except perhaps in large rider operator machinery.

An object of the present invention is the provision of a new and improved walk behind floor surfacing machine, and particularly a drum sanding machine.

Another object of the present invention is the provision of a self-propelled driving unit and coupling arrangement for walk behind floor surfacing machinery, and particularly drum sanding machines.

A still further object of the present invention is the provision of a new and improved floor surfacing machine and propelling unit assembly which allows the propelling unit and machine to be quickly separated and the floor surfacing machine swung out of position for ready access to its floor surfacing element, as for example the sanding drum, that is located in the front end of the machine.

Further objects and advantages will become apparent to those skilled in the art to which the invention relates from the following description of several preferred embodiments described with reference to the accompanying drawings forming a part of this specification, and in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of an assembly of a walk behind drum type floor sander, and a propelling unit therefore which embody principles of the present invention;

FIG. 2 is a side elevational view of the assembly shown in FIG. 1;

FIG. 3 is an enlarged cross sectional view taken approximately on the line 33 of FIG. 2;

FIG. 4 is a fragmentary sectional view taken approximately on the line 4-4 of FIG. 2; and

FIG. 5 is a side elevational view similar to FIG. 2 but showing another embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS shown inthe drawings is of conventional construction and comprises a rigid cast housing 12 having a sanding drum l4 journaled in the front end of the housing. The sanding drum 14 is driven by a 3 HP. motor which sits on top of the housing and is connected to the sanding drum 14 by a V-belt drive, not shown. Immediately rearwardly of the sanding drum there are a pair of main support wheels 16 which are coaxially located and which can be raised and lowered relative to the housing 12 to move the drum 14 off of the floor when so desired. The main support wheels are raised and lowered by mechanism, not shown, which mechanism is of conventional construction. This mechanism also is adjustable to provide a desired weight distribution between the sanding drum 14 and the wheels 16 when the wheels are in their upper position for affecting drum engagement of the floor. The wheels 16 are nonswivetable so as to restrain the sanding drum from lateral movement when the drum is sanding the floor. The floor sander 10 also includes a single rear swivetable wheel 18 which allows the rear end of the sander to be moved in any direction when pulled or pushed by the handle 20. The sander further includes the usual dust collecting equipment which forms no part of the present invention and which will not be described. The rate of material removed by the sanding drum 14 is a function of the horse power that is delivered thereto as well as the weight that is exerted on the sanding drum to force it into engagement with the floor. Since the unit is intended to be moved about manually, it can be no heavier than necessary to perform its sanding operationwith the result that when the sanding drum is in engagement with the floor, insufficient weight remains on the main support wheels 16 to provide good tractron.

According to principles of the present invention a power drive for the sander is provided by a separate power drive unit 22 that is positioned forwardly of the sander and which is connected to the sander by means of a draw frame 24, later to be described. The power drive unit 22 comprises a pair of coaxially positioned main support wheels 26 that are'suitably journaled and supported from the units frame or chassis 28. The axle which supports the wheels 26 is provided with a sprocket 30 that is chain driven from a sprocket 32 on the power output shaft of a gear reducer 34. Power input to the gear reducer 34 is supplied by the /3 HP. electric motor 36, variable speed pulley 38, V-belt 40, and pulley 42 affixed to the input shaft of the gear reducer 34. A pair of swivetable castors 44 are mounted onto the front end of the chassis 28 to make the drive unit self-supporting, and allow it to be steered over the floor at appropriate times. The motor 36 is supplied with power through the cord 46 and a motor rotation changing switch 48 that is connected with the power supply to the sander. The motor 36 is of the type which can be run in either direction.

Movement of the drive unit 22 is transmitted to the sander by the draw frame 24. The draw frame 24 cmprises a plate 50 having a piano type hinge 52 welded to the front end. The piano type hinge 52 is bolted to the chassis 28 using suitable fasteners and spacer washers for proper alignment. The rear end of the frame 24 is also provided with a hinge comprising a section of half inch pipe 60 and a pair of short sections 62 positioned on opposite sides of the pipe 60. The sections 62 are in turn welded to the upstanding leg of an angle iron 64, which in turn is bolted to the housing 12 of the sander by suitable fasteners 66. An L-shaped pin 68 passes through the pipe sections 60 and 62, and the projecting end of the L-shaped pin has a small hole with a cotter pin 70 therein, so that the pin 68 can be easily and quickly withdrawn and the units separated. In the embodiment shown, the frame 24 extends downwardly and forwardly at approximately a 30 angle, so that the sanding action of the drum 14 at all times pushes the draw frame 24 forwardly and downwardly to thereby provide additional traction for the drive wheels 26.

The drive wheels 26 of the drive unit are adapted to be lifted off of the floor, so that the unit can be moved laterally by means of a lever 72 whose front end is suitably affixed to the chassis 28 of the drive unit. In the embodiment shown, a short section of pipe 74 is welded to the chassis 28 using a suitable gusset for stiffening, and the lever 72 is inserted therein and suitably bolted in place. The rear end of the lever 72 extends along the side of the sander and is connected to a pull rod 76 by means ofa swivetable connection. The swivetable connection is formed by a short threaded bar 78 which is screwed onto the threaded lower end of a pull rod 76. The bar 78 carries a laterally projecting pin 80 that is received in a hole 82 in the rear end of the lever 72. A nut 83 is provided on the outer end of the pin 80 to prevent its withdrawal from the hole 82. The other end of the rod 76 is bent laterally and received in a hole 84 of an over-center handle 86 that is suitably pivoted to the handle support 88 of the machine. By rotating the handle 86 over-center from its lower position to its upper position against a suitable stop, not shown, the lever 72 is, pulled upwardly sufficiently to raise the drive wheels 26 out of engagement with the floor and cause the weight of the drive unit 22 to be shifted onto the castors 44. In this condition, the drive unit can be swung laterally provided the operator has also lowered the wheels 16 to raise the sanding drum 14 out of engagement with the floor. The entire assembly at this time will, therefore, be free to pivot about the main drive wheels 16 with the sanders rear wheels 18 swiveling in one direction, and the castors l4 swiveling in the opposite direction.

Not only does the driving unit pull or push the sanding machine across the floor as desired by the operator, butit also provides a restraint against lateral movement of the front end of the sander when its drum 14 is sliding vigorously against the floor. As previously explained, the driving unit 24 includes a pair of nonsteering wheels 26 and is connected to the sander through a draw frame that restrains all relative movement between the power driving unit and the sander, except up and down movement as accommodated by the front and rear hinge structures 52 and 60, 62. When the drive means 26 are in engagement with the floor,

therefore, two pair of non-steerable wheels are provided with one pair 26 forwardly of the sanding drum l4 and the other pair 16 rearwardly of the sanding drum 14. The stability added by the 'driving unit 22 is very great. An operator of a sander without the driving unit 22 attached must not only pull the sander against the sanding action of the drum 14', but most continually guide the sander against lateral movement. An operator of a sander having the drive unit 22 attached need only properly position the assembly at one end of a bowling alley and start the unit. The driving unit thereafter will move the sander at a controlled rate of speed and in a straight line to the'other end of the alley to give a more uniform sanding operation than is possible with manual movement of the sander.

When it is desired tochange thesandpaper on the drum 14, the cotter pin is pulled from the L-shaped pin 68 and the L-shaped pin 68 is pulled from the pipe sections 60 and 62 to allow the draw frame 24 to be swung upwardly out of the way. Since the lever 72 is pushing the rear end of the sander towards the lever 72 to cause the sander to turn at a sharper angle than does the power unit 22 until such time as the front end of the sander faces free and clear of the power unit 22. At that time the entire front end of the sander22 is exposed so that the old sandpaper can be removed and new sandpaper installed on the drum 14 without disconnecting the lever 72 from the handle 86. When it is desired to couple the sander 10 to the power unit 22 again, the front end of the sander will be turned towards the power unit and pushed forwardly to pivot about the wheels 16 and bring the pipe sections 60 and 62 in proper alignment. When the pipe sections are in alignment, the L-shaped pin 68 is installed, and cotter pin 70 put in place to complete the coupling operation.

Because the driving unit 22 provides added stability against lateral movement, its use will allow greater latitude in the design of walk-behind type floor sanders, as shown in FIG. 5. In the embodiment shown in FIG. 5, a non-steerable support wheel is provided at the rear end of the sander and swivetable wheels or castors are provided just readwardly of the sanding drum. Those portions of the embodiment shown in FIG. 5 which correspond to similar portions of the embodiment shown in FIGS. 1 through 4 are designated by a like reference and are characterized further in that a suffix a is affixed thereto. The non-steerable wheel 16a are made semi-retractable to lift the drum 14a out of engagement with the ground by means of a rocking action about the castors 18a. The castor wheels 18a are adjustable and are provided with suitable spring tension to adjust the amount of weight that is applied to the sanding drum 14a as was done in the previously described embodiment. With the embodiment shown in FIG. 5, the sander can be swung laterally from behind the power driving unit 22a by pivoting about the right rear wheel without pulling the machine longitudinally over the floor.

While the invention has been described in considerable detail, I do not wish to be limited to the particlar embodiments shown and described, and it is my intention to cover hereby all novel adaptations, modifications, and arrangements thereof which come within the practice of those skilled in the art to which the invention relates.

I claim:

1. A power driving unit for a floor sander of the type having a pair of coaxial non-swivetable main support wheels and a swivetable support wheel spaced longitudinally thereof, said power driving unit comprising: a

. chassis, a pair of coaxial non-swivetable main floor engaging wheels for said chassis, a swivetale support wheel for said chassis spaced longitudinally of its main wheels, a motor on said chassis, drive means connecting said motor with one of said main support wheels of said unit, a draw frame, first hinge means connecting said draw frame to said chassis, second hinge means for connecting said draw frame to the floor sander, said hinge means being constructed and arranged to prevent I turning motion between said driving unit and the floor sander but to permit vertical rocking action of the driving unit relative to the floor sander, a lever fastened to said chassis in a position to extend rearwardly externally of one side of the sander, and means'adapted to be secured to the rear of the sander for raising or lowering said lever to lift the weight of said driving unit off of its drive wheels and onto its swivetable support wheel, and whereby the sander is automatically heldin a straight line by the driving unit when the lever is moved to bring the power unit into its driving condition and the sander and power unit can be pivoted about the main support wheels of the sander when the lever is moved to bring the driving unit into its non-driving condition.

2. The power driving unit of claim 1 wherein said drive wheels are at the rear of the driving unit with said swivetable support wheel forwardly thereof, and a mounting for said second hinge meansconstructed and arranged to support the rear of said draw frame at an elevation above said first hinge means and whereby the pushing action of the sander against the driving unit forces the driving wheelsonto the floor.

3. The power driving unit of claim 1 wherein said driving wheels are at the rear of the driving unit with said swivetable support wheel forwardly thereof, an over-center handle, a pull rod for connecting said overcenter handle to the rear of said lever, and said swivetable connection between said pull rod and said lever, and whereby said handle, pull rod and lever can stay connected when the driving unit and sander are separated at said draw frame.

4. A power driving unit for a floor sander of the type having a pair of coaxial non-swivetable main support wheels with a sanding drum forwardly thereof and a swivetable support wheel rearwardly of the main wheels, said power driving unit comprising: a chassis, a pair of coaxial non-swivetable main floor engaging support wheels at the rear of said chassis, a swivetable support wheel forwardly of said main wheels, a motor on said chassis, drive means connecting said motor with one of said main support wheels of said unit, a draw frame, first hinge means connecting the front of said draw frame to said chassis, and second hinge means constructed and arranged to connect the rear of said draw frame to a location on said sander at an elevation above said first hinge means, said hinge means being constructed and arranged to prevent turning motion between said driving unit and the floor sander but to permit vertical rocking action of the driving unit relative to the floor sander.

5. The power driving unit of claim 4 and including: a lever fastened to said chassis in a position to extend rearwardly externally of one side of a floor sander, an over-center handle, a pull rod for connecting said overcenter handle to the rear of said lever, and a swivetable connection between said pull rod and said lever.

6. An assembly of a floor sander and a separable power driving .unit therefor, comprising: a driving unit chassis, a pair ofcoaxial non-swivetable main floor engaging support wheels at the rear of said chassis, a

swivetable support wheel forwardly of said main wheels, a motor, on said chassis, drive means connecting said motor with'one of said main support wheels of said unit, a draw frame, first hinge means connecting the front of said draw frame to said chassis, second hinge means constructed and arranged to connect the rear of said draw frame to a location on said sander at an elevation above said first hinge means, said hinge means being constructed and arranged to prevent turning motion between said driving unit and the floor sander but to permit vertical rocking action of the driving unit relative to the floor sander, a lever fastened to said driving unit chassis in a position to extend rearwardly externally of one side of the sander, an over-center handle pinned to said sander, a pull rod for connecting said over-center handle to the rear of said lever, and a swivetable connection between said pull rod and said lever.

7. An assembly comprising. a floor sander having a sanding drum on the front end thereof, a pair of coaxial non-swivetable main support wheels at the rear of said sander, a pair of swivetable wheels adjacent the front of said sander, a power driving unit chassis, a pair of coaxial non-swivetable main floor engaging support wheels at the rear of said chassis, a swivetable support wheel forwardly of said main wheels, a motor'on said chassis, drive means connecting said motor with one of said main support wheels of said unit, a draw frame, first hinge means connecting the front of said draw frame to said chassis, second hinge means constructed and arranged to connect the rear of said draw frame to a location on said sander at an elevation above said first hinge means, said hinge means being constructed and arranged to prevent turning motion between said driving unit and the floor sander but to permit vertical rocking action of the driving unit relative to the floor sander, a lever fastened to said driving unit chassis in a position to extend rearwardly externally of one side of the sander, an over-center handle pinned to said sander, a pull rod for connecting said over-center handle to the rear of said lever, and a swivetable connection between said pull rod and said lever. 

1. A power driving unit for a floor sander of the type having a pair of coaxial non-swivetable main support wheels and a swivetable support wheel spaced longitudinally thereof, said power driving unit comprising: a chassis, a pair of coaxial nonswivetable main floor engaging wheels for said chassis, a swivetale support wheel for said chassis spaced longitudinally of its main wheels, a motor on said chassis, drive means connecting said motor with one of said main support wheels of said unit, a draw frame, first hinge means connecting said draw frame to said chassis, second hinge means for connecting said draw frame to the floor sander, said hinge means being constructed and arranged to prevent turning motion between said driving unit and the floor sander but to permit vertical rocking Action of the driving unit relative to the floor sander, a lever fastened to said chassis in a position to extend rearwardly externally of one side of the sander, and means adapted to be secured to the rear of the sander for raising or lowering said lever to lift the weight of said driving unit off of its drive wheels and onto its swivetable support wheel, and whereby the sander is automatically held in a straight line by the driving unit when the lever is moved to bring the power unit into its driving condition and the sander and power unit can be pivoted about the main support wheels of the sander when the lever is moved to bring the driving unit into its non-driving condition.
 2. The power driving unit of claim 1 wherein said drive wheels are at the rear of the driving unit with said swivetable support wheel forwardly thereof, and a mounting for said second hinge means constructed and arranged to support the rear of said draw frame at an elevation above said first hinge means and whereby the pushing action of the sander against the driving unit forces the driving wheels onto the floor.
 3. The power driving unit of claim 1 wherein said driving wheels are at the rear of the driving unit with said swivetable support wheel forwardly thereof, an over-center handle, a pull rod for connecting said over-center handle to the rear of said lever, and said swivetable connection between said pull rod and said lever, and whereby said handle, pull rod and lever can stay connected when the driving unit and sander are separated at said draw frame.
 4. A power driving unit for a floor sander of the type having a pair of coaxial non-swivetable main support wheels with a sanding drum forwardly thereof and a swivetable support wheel rearwardly of the main wheels, said power driving unit comprising: a chassis, a pair of coaxial non-swivetable main floor engaging support wheels at the rear of said chassis, a swivetable support wheel forwardly of said main wheels, a motor on said chassis, drive means connecting said motor with one of said main support wheels of said unit, a draw frame, first hinge means connecting the front of said draw frame to said chassis, and second hinge means constructed and arranged to connect the rear of said draw frame to a location on said sander at an elevation above said first hinge means, said hinge means being constructed and arranged to prevent turning motion between said driving unit and the floor sander but to permit vertical rocking action of the driving unit relative to the floor sander.
 5. The power driving unit of claim 4 and including: a lever fastened to said chassis in a position to extend rearwardly externally of one side of a floor sander, an over-center handle, a pull rod for connecting said over-center handle to the rear of said lever, and a swivetable connection between said pull rod and said lever.
 6. An assembly of a floor sander and a separable power driving unit therefor, comprising: a driving unit chassis, a pair of coaxial non-swivetable main floor engaging support wheels at the rear of said chassis, a swivetable support wheel forwardly of said main wheels, a motor on said chassis, drive means connecting said motor with one of said main support wheels of said unit, a draw frame, first hinge means connecting the front of said draw frame to said chassis, second hinge means constructed and arranged to connect the rear of said draw frame to a location on said sander at an elevation above said first hinge means, said hinge means being constructed and arranged to prevent turning motion between said driving unit and the floor sander but to permit vertical rocking action of the driving unit relative to the floor sander, a lever fastened to said driving unit chassis in a position to extend rearwardly externally of one side of the sander, an over-center handle pinned to said sander, a pull rod for connecting said over-center handle to the rear of said lever, and a swivetable connection between said pull rod and said lever.
 7. An assembly comprising: a floor sander having a sanding drum on the front end thereof, a pair of coaxial non-swivetable main support wheels at the rear of said sander, a pair of swivetable wheels adjacent the front of said sander, a power driving unit chassis, a pair of coaxial non-swivetable main floor engaging support wheels at the rear of said chassis, a swivetable support wheel forwardly of said main wheels, a motor on said chassis, drive means connecting said motor with one of said main support wheels of said unit, a draw frame, first hinge means connecting the front of said draw frame to said chassis, second hinge means constructed and arranged to connect the rear of said draw frame to a location on said sander at an elevation above said first hinge means, said hinge means being constructed and arranged to prevent turning motion between said driving unit and the floor sander but to permit vertical rocking action of the driving unit relative to the floor sander, a lever fastened to said driving unit chassis in a position to extend rearwardly externally of one side of the sander, an over-center handle pinned to said sander, a pull rod for connecting said over-center handle to the rear of said lever, and a swivetable connection between said pull rod and said lever. 